Archive for February, 2011

Peer assessment of lab work

Wednesday, February 23rd, 2011

Spectacle chandelier by seq on flickr

We’ll be doing an experiment to compare the properties of ionic and covalent substances, and to then relate these properties to the types of bonding in them.  Here’s the instruction sheet: LAB – How are the properties of substances explained by theories of bonding and structure

Once you have written up the lab report, you will peer assess it using these rubrics.  FINALRubric DCP   FINAL Rubric CE  The first one (DCP) looks at your data collection.  The second one (CE) looks at your conclusion and evaluations.  A few of your classmates can give you feedback, which you can then act on before you submit the final version to me.

Photosynthesis

Friday, February 18th, 2011

Jatropha hybdrid - leaf detail by tonrulkens on flickr

And here is the sing-along song for this topic.

For notes on the SL portion of the syllabus, here is a useful powerpoint.  Photosynthesis  This is the core material from our favourite teacher in Indonesia.  Once you have grasped the basics, move on to this HL stuff.

We’ll cover a lot of interesting ideas in this unit.  How are plants affected by light of different wavelengths?  What is the relationship between structure and function in chloroplasts? What is meant by limiting factors in determining photosynthetic rate?  How can we measure photosynthesis?  And, of course, we’ll delve into the biochemical pathways of the light dependent and light independent reactions.

Useful video for labs.

There are 3 online photosynthesis simulations that we will use.  This first one is nice and simple and should help get you started on your design lab.  This one is also easy to use.  This third one is more complicated, and you might want to come back to it as we go through the topic.

Lewis structures and bonding

Tuesday, February 15th, 2011

Carbon dioxide octet dot cross from wikimedia commons

As a good introduction to bonding, watch this and sing along!

An ion is a charged atom – one that has gained or lost electrons in order to complete it’s outer shell and become stable.  Elements in Group 1 form ions with a charge of +1, since they lose 1 valence electron and end up with one more proton than electron.  Elements in Group 7 form ions with a charge of -1, since they gain 1 valence electron and end up with one more electron than proton.  The bond that is formed when a metal and a non-metal react in this way is called an ionic bond.  In an ionic bond, electrons are donated or received.

Covalent bonds form between non-metal elements.  This could be between the same non-metals (eg. O2) or different non-metals (eg. CO2).  In a covalent bond electrons are shared between the elements to complete the outer shells.  We use Lewis structures to represent this.  Click here for instructions on how to draw Lewis structures (also known as “dot and cross” diagrams).

To practice drawing these diagrams, here are some useful links:-

This site allows you to build your own molecules with single, double and triple covalent bonds.  If you don’t do any others, DO THIS ONE.

This one wold be good for review at the end of the topic.  It generates some multiple choice questions for you to practice identifying the correct Lewis structure.

Finally, this site allows you to construct Lewis diagrams.  It is quite advanced, but some of you might enjoy the challenge 🙂

Empirical formulae

Tuesday, February 15th, 2011

House of Blue by nuttyxander on flickr

What is the difference between molecular and empirical formulae?  You need to find out.  Here is a set of practice questions on this topic.  7 emp form

This week we’ll do a lab where we determine the formula of hydrated copper (II) sulfate by experimental methods.  Read the lab sheet: formula of hydrated copper sulfate

To help you practice, there are tons of great resources out there on the web.  I have selected 4.  They are listed here in order of increasing complexity.

1. Nice worked examples.  2.  Another worked example for you to click through to find the solution. 3. Worked examples with extra problems, answers given.  4.  Fairly lengthy explanation of how to perform calculations. 

For some online practice, try this site.  And this worksheet has some excellent questions.  If you can do these you are all set!  Empirical and Molecular Formula Questions

The mole

Monday, February 7th, 2011

 

Dearest mole by zenera on flickr

We are going to step into some deep and sticky chemistry – and take a look at the term mole.  This is an important concept, so we’ll take it slow and steady.  This is a great resource to help us work our way through the topic.  Come back and revisit it often – until you feel you have a handle on it.  Practice, practice, practice! 

More useful information here.

Cellular respiration

Monday, February 7th, 2011

Respiration is NOT breathing!  Ok, now I’ve got that off my chest, let’s continue 🙂

This is going to be some of the more challenging work we cover, but it is good stuff!  Start with this presentation.  Once you feel you have a handle on that, then move on to this one.  Once again, huge gratitude to Mr Taylor in Bandung for his work. Finally, here are the basics, summarized: Cell Respiration

A few good online resources to help you through this topic:    Cellular respiration songYouTube Preview Image

We’ll do a lab where we burn peanuts to simulate cell respiration (you said no-one had allergies, right?). Burning peanuts to simulate cellular respiration

Periodic Table

Thursday, February 3rd, 2011

Periodic Table on a taxi by geofones on flickr

We need to get to know the Periodic Table very well.  To help us we will use the following resources (thanks Mr Goodman!) and this linkThis site will also be invaluable to recap what we talk about in class.

mendeleev

The_periodic_table

patterns in PT

And here is a homework assignment for you.  PT_scavenger_hunt

We will talk about trends and patterns in the periodic table, specifically Group 1 (alkali metals) and Group 7 (halogens).  We will make observations about reactions of the alkali metals with water.  Li and Na we can do in class, but for the more reactive elements we’ll have to be content with watching this video.